How do you improve your marks in your LOTE subject?
Personally, I focused on learning the language rather than just learning for marks. This makes you more flexible and makes everything a little less stressful—I could never understand why people got so freaked out about LOTEs! I think this may have been the key difference.
The way to do that, participate in the language. Try to incorporate it into your every day life. Follow a facebook page in that language that posts lots of memes, that's always fun!
These things will improve your general skills and therefore improve your marks as well.
As far as actually working to marks goes though, make sure you practise in context. If you're going to be doing a writing task, prepare for it by writing. If you're doing an aural task, listen. Reading task, read. Oral task, speak. I cannot stress the importance of this enough. Those who do well on the oral exam for example are those who have practised speaking, not people who have written 100 pages of notes on their detailed study. You need to practise skills in context! That's why you get these different assessments because they are different skills that you need for the exam, but more importantly, they are different skills you need to be able to communicate effectively in that language. Those assessments are there are to force you to use and develop those skills, so it's expected that you do the same at home. If you learn in one dimension, you will only be able to operate in that dimension.